I occasionally wire portable pumps with self-contained 3 ph. starters mounted on the unit. They are fed by plugging into 20 amp branch ckts. A typical size is 1.5 HP (3 amps @ 480 volt). Article 400-13(OC protection for the cords) refers to 240-4. 240-4(a) requires OC protection in accordance with the cords ampacity per table 400-5(A), which requires 12 gauge cord for 20 amps. However, 240-4 allows supplementary OC protection as in 241-10 to protect the cord. Is the OL relay in the starter considered to be this supplementary OC protection, and therefoe, can I use cord smaller than #12, based on OL heater size?
Sparky, Thanks. But I'm still hung up on supplementary OC protection as mentioned in 240-4(a). This would allow me to use 14/4 or even 16/4, instead of 12/4 to supply the starter. Remember, it's pulling less than 3 amps, so voltage drop shouldn't be much of a problem. If I can use smaller cable, I'd like to. We usually put about 35' of cord on the pump, and 12/4 can be a nuisance for the operators.
ok, 210-4(a) does refer to 400-5. 240-9 would seem to side with you here. I was looking for some reference in 430, to either code loop there or 'amend' the loop out. I guess i'm still sittin' the fence here
Re: Portable cord sizing#78060 08/14/0107:31 AM08/14/0107:31 AM
Well i've gone back and forth here, seems you got a winner. Lemme play devil's advocate... Suppose you had a setup with an adjustable setup, like those new Furnace jobs that can 'dial-in' what you need. Per code that setting can be played with, so would we size to the upper limit of the range???
Originally posted by sparky: Well i've gone back and forth here, seems you got a winner. Lemme play devil's advocate... Suppose you had a setup with an adjustable setup, like those new Furnace jobs that can 'dial-in' what you need. Per code that setting can be played with, so would we size to the upper limit of the range???
I have 2 of those animals(Smart OL Relay?) on the shelf right now. Allen-Bradley, though. I'm home now, but I recall that even thuogh they are adjustable, you have to choose from a few different ranges for each size starter. This narrows it down somewhat. So, even adjusting all the way up, you won't be going very far for a given relay.